Geeky Question: Fingernail size /profile on strong climbers?

When pictures or video show close-ups of strong climbers' hands (say, when they're gripping the rock), it frequently appears to me that their fingernails are relatively broad in comparison to their fingertip. I believe a more precise statement is that their "lateral nail fold" is relatively narrow compared to the overall population. Is there adaptation / shaping of the nail (or distal phalange part of the finger) that occurs with repeated / hard stimuli? Just coincidence?